Method for the production of aluminum hydroxide



Patented May 19, 1925.

UNITED STATES PATENT'OFFICE.

ARTHUR J. MOXHAM, 0'1? ODESSA, DELAWARE, ASSIGNOR. BY MESNE ASSIGNMENTS, TO J. P, LAFFEY, TRUSTEE, OF WILMINGTON, DELAWARE.

HETHOD FOR THE PRODUCTION OF ALUMINUM HYDBOXIDE.

No Drawing.

To all whom if may conccrn.

Be it known that I, Alrrru'n J. MoxHaM, a subject of the King of Great Britain, and a resident of Odessa. in the county of New ('astlc and State of Delaware. and whose ost-oflice address is 101 Park Avenue. New

ork, N. Y., have invented a new and useful Method for the Production of Aluminum Hydroxide, of which the following is a specification.

M invention relates to the manufacture of a umina from minerals containing it and involves particularly a method for producing aluminum by precipitation of aluminum hydroxide from solutions containing sulfate of aluminum, including especially solutions containin ture w it sulfates of potassium and/or iron. I have discovered that if metallic iron is added in the proper proportion to a solution of aluminum sulfate or of these mixed sulfates the aluminum will be precipitated in the form of the h droxide, and if the potassium and iron su fates are present they will remain in solution as potassium sulfate and ferrous sulfate. An-

-other feature of my invention' involves the method of treating solutions containing sulfates of aluminum, potassium and iron by first producing the aluminum hydroxide in this manner and then separating the other sulfates by crystallization.

My invention is applicable to solutions obtained by treating greensand or glauconit'e with sulfuric acid, but this application is not limited to solutions thus obtained. I will, however, describe the preferred process of treating such a solution as is obtained when greensand orglauconitc has been treated with sulfuric acid and the silicious resi due se arated to produce a clear solution of sul ates ofiron, potassium and aluminum.

The iron sulfate in .this solution will he principally in'ferric form, but there may also be some ferrous sulfate in solution. Ac-. cording to the nature of the leaching operation, the solution ma have some free acid or may be substantially neutral.

To the clear solution, while still hot, I add enough iron scrap, preferably in the form of turnings or sheet lI'OIl scrap, or such other scrap as will dissolve quickly. Enough of this iron scrap is added to combine with all the SO, present in the sulfate of aluminum and in any free acid present and to sulfate of aluminum in admix- Appllcation filed December 7, 18%. serial No. 679,269.

combine with the ferricsulfate in solution to reduce it to ferrous sulfate. It is best to stir or agitate the solution during reaction. The sulfate of potassium will retain its arid and will be inert to the reaction, but the aluminum will eagerly give up its acid to the iron after the ferric sulfate has been reduced to ferrous sulfate, which will remain in solution. The aluminum sulfate has thus become aluminum hydroxide, which will precipitate.

The equation of the reaction which produces the aluminum hydroxide is:

For the sulfate of aluminum based on the crystals (hydrates) For potash alum (crystal basis) The reaction which reduces the ferric sulfate to ferrous sulfate has the following equation:

The final result is that all thetlumlhum pre ent will be 1 u-ccipitated as aluminum ydroxidc, the erric sulfate will be reduced to ferrous sulfate, and, in conjunction with the sulfate of potassium, will remain in solution.

I find it necessary to obtain ture of from 90 C. to 95 C. to properly start the reaction, as it is a sluggish one at a lower temperature. This temperature may be obtained by waste steam, but the previous leaching and separation of the silicious residue may be so conducted that the solution, immediatelv after sep ation, is at this temperature. nce the reaction is started, the heat quickly increases, the action being an exothermic one.

The precipitated hydroxide of aluminum is filteredorotherwise separated' from the accompanying solution and is washedht'he washing being added to the next leach. This aluminum may be used either as the hydroxide, or by cul -inntion it can be converted to dry alumina.

a tempera- The heat evolved during the reaction can be utilized, by regulating the amount of water added to the leach to avoid expenditure of heat in boiling 01? an excess of Water to bring the solution down to the proper concentration (between 1.40 and 1.50 specific gravity at normal temperature) for the purpose of crystallizing out the copper-as or ferrous sulfate. The mother liquor remaining can then be concentrated to give up its sulfate of potassium and its ferrous sulfate. fWith iron as the only reagent added to the solution of mixed sulfates, the salts have been castrated; the alumina by precipitation an tile on peras and sulfate of potassium by crysta ization.

There are thus obtained as final products, aluminum hydroxide, sulfate of otassium and copperas. A

As a modification of the process as specifically described'l first crystallize out potash alum from the solution of the mixed sulfates, leaving the ferric sulfate insolution. The potash alum may thenbe utilized as a final product, or as an alternative t may "*9 dissolved in water and this aqueous solution'then treated with metallic iron, as above described, to precipitate the aluminum hy- "Lbeing awn separated n:

dronide the sulfate. 0 tassium solution b fissu sye was 9 e sulfate solutionflma falso he treated jvith metallic iron to use 'itTto ferrous "sulfate and than I I can obtain as fine products, alum, aluminum hydroxide, sulfate of potassium and copperas.

This modification of the process issomewhat more costly than the method previ ously described, but in the leaching of 'jglauconite or other material containing alumina there becomes ;arailable a number of salts ha'ving very different market demands, which demands are themselves changeable. Hence, it becomes advantageous tobe able to change the nature of the product duri the process of manufacture to suit such 0 an'ges in market as may occur.

During the operations described herein, little or no fuel is called-for. The method is equally applicable to those alumina ores containing little or no iron as kaolin, felds ar derivates and the like. In these cases t are will be only a small amount of copperas produced; with the glauconite a relatively small amount of alumina and a larger amount of 'copperas.

I claim:

1. The process of extractin alumina from minerals containing it, whic involves first treating the mineral to obtain a solution of aluminum sulfate and then adding metallic iron to the solution to decompose the suiggate' nnd precipitate elumigum hydroxide.

stailizedr In this case 2. The process of extracting alumina from minerals containing it which involves first treating the mineral to obtain a solution of aluminum sulfate andfihen adding metallic iron to the solution while it is at a temperature of C, or over to decompose the sulfate and precipitate aluminum h 'droxicle.

3. The process of Se arating an extract inglalumina and otas from minerals containing both which involves first trsatin the mineral to obtain aluminum sulfate em potassium sulfate together in solution, than adding metallic iron to the solution to d compose the almninum sulfate and preci tutc aluminum hydroxide, then separatiil the aluminum hydroxide from the sciatic.

4. The process of separating and extracl ing alumina and potash from minerals con luining both which. involves first treatin the mineral to obtain aluminum sulfate and potassium sulfate together in solution, then adding metallic iron to the solution While it is at a temperature of 90 C. or over to decompose the aluminum sulfate and precipitate aluminum hydroxide, then separating the aluminum hydroxide from the solu- 5. The process of extractin alumina from minerals containing it an ferric oxide which involves first treating the mineral to obtain a solution containing aluminum sul fate and ferric sulfate, then adding metallic iron to the solution in sufiicient quantit to reduce the ferric sulfate to ferrous fate and to decompose the sulfate of aluminum and precipitate aluminum h droxids, and then separating the precipitate from the solution.

6. The process of treatin minerals containing ferric oxide, potas which involves treating the mineral to ob tain aluminum sulfate, ferric sulfate and potassium sulfate in solution together, then adding metallic iron to the solution in suflicient quantity to combine with the ferric sulfate to reduce it to. ferrous sulfate and to decompose the sulfate of aluminum, causing suoh reactions to meurgwith preci itation of aluminum hydroxide, separating t eprecipitate from the solution. i -f l 7. The "methodgpfgrocluciir alumina from sulfate of ultiminumlin solo ion which conastsan adding metallic iron to such solution'and causing a reaction to decompose -the sulfate and'precipitate aluminum hydroxide.

8. The method of producing alumina from sulfate of aluminum in solution which.

consists in adding metallic iron to such solution and causing a regggiofi to decompose, the sulfate and Freci fitate aluminuin' h droxide, and final y es. cining the hydiidmd e.

9. The method as sglcified in claim 7 when the solution is at apparatus of 90 C; or over, to initiate the reaction.

and alumina,

ill]

10. The method as specified in claim 8 the precipitate from the ferrous sulfate sowhen the solution is at a temperature of 90 ,C. or over, to initii'ite the reaction.

11. The method of treating solutions containing sulfate of aluminum andsulfate of potassium which consists in adding metallic iron to such solution, causing a reaction to decompose the sulfate of aluminum and precipitate aluminum hydroxide, separating the precipitate from the'solution and separatin the ferrous sulfate from' the potassium su fate b'y crystallization. t

" 12. The method as specified in claim 11 when the solution is at a temperature of 90 C. or over to initiate the reaction.

13. The method of treating solutions containing ferric sulfate and aluminum sulfate which consists in adding metallic iron to the solution in a sufficient quantit to reduce the ferric sulfate to ferrous sul ate and to decompose the sulfate of aluminum cans ing such reaction to effect such reduction and decom osition with precipitation of 7 aluminum iydroxide, and then separating lution. I

14. The process asspecified in claim 1? when the solution is at a temperature of 90 C. or over to initiate the reaction.

15. The process of treating solutions containing sulfate of aluminum, sulfate of potassium, and ferric sulfate which consists in adding metallic iron to the solution in sufiicient quantity to reduce the ferric sulfate to ferrous sulfate and to decompose the sulfate of aluminum, causing suchreat-tion to occur with precipitation of aluminum hydroxide, separating the precipitate from the solution, and separating the ferrous sulfate from the potassium sulfate by crystallizw tion.

16. The process as specified in claim 15 when the solution is at a temperature of 90 C. or over to initiate the reaction In testimony whereof, I have signed my nnme to this specification.

IAR'rnUR J. MOXHAM.

fate by crystallization.

10. The method as specified in claim 8 when the solution is at a temperature of 90 C. or over, to initiate the reaction.

ll. The method of treating solutions containing sulfate of aluminum and sulfate of potassium which consists in adding metallic iron to such solution, causing a reaction to decompose the sulfate of aluminum and precipitate aluminum hydroxide, separating the precipitate from the solution and separating the ferrous sulfate from the potassium sul- 12. The method as specified'in claim 11 when the solution is at a temperature of 90 C. or over to initiate the reaction.

13. The method of treating solu! ions containing ferric sulfate and aluminum sulfate which consists in adding metallic iron to the Solution in a sufficient quantit to reduce the ferric sulfate to ferrous sul ate and to decompose the sulfate of aluminum causing such reaction to effect such reduction and decomposition with precipitation of aluminum hydroxide, and then separating the precipitate from the ferrous sulfate solution.

14. The process as specified in claim 1? when the solution is at a tcmpcraturtof 90 C. or over to initiate the reaction.

1."). The process of treating solutions containing sulfate of aluminum, sulfate of potassium, and ferric sulfate which consists in adding metallic iron to the solution in sufficient quantity to reduce the ferric sulfate to ferrous sulfate and to decompose the sulfate of aluminum, causing such reaction to occur with precipitation of aluminum hydroxide, separating the precipitate from the solution, and separating the ferrous sulfate from the potassium sulfate by cr \'stallization.

16. The process as specified in claim 15 when the solution is at a temperature of 90 C. or over to initiate the reaction.

In testimony whereof, I have signed my namelo this specification.

fan'riiun LI. MOXHAM.

Certificate of Correction.

It is hereby certified-that in Letters Patent No. 1,538,839, granted May *19, 1925,

uponthe a lication of Arthur J. Moxham, of Odessa, De

merit. in

laware, for an improveethods for the Production of Aluminum Hydroxide, errors appear in the printed specification requiring correction as follows: Page 1, line 72, in the formulahbefore 3Fe insert a plus sign same page, line 78, before i insert the numeral 2; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 1st day of September, A. D. 1925.

KARL FENNING, Acting Commissioner of P a-tents.

Cerflflcate of Correction. It is hereby certified-that in Letters Patent No. 1,538,839, granted May 19, 19%,

uponthe a. lication of Arthur J. Moxham, of Odessa, Delaware, for an impruvementin ethods for the Production of Aluminum Hydroxide, errors appear in the printed specification requiring correction as foliows: Page 1, line 72, in the formula before 3Fe insert. a plus sign same page, line 78, before [Mail-1),] &insert the numeral 2; and that the said Letters Patent should be read with these corrections therein that the same may conform to the I'QCOILI of the case in the Pamnt ()fiioe.

Signed and sealed. this 1st day of &ptember, A. D. 1925.

[BELL] KARL FENNING,

Acting Commias-iomr of Patents. 

